1. Field of Technology
Embodiments disclosed herein relate to an envelope tracking power amplifier system, and more specifically to calibrating delay in an envelope tracking power amplifier system.
2. Description of the Related Arts
In an envelope tracking (ET) power amplifier (PA) system, a power supply supplies a dynamically changing supply voltage to the PA. The supply voltage to the PA adjusts as the amplitude of the radio frequency (RF) signal to the PA changes such that the PA operates at or near peak efficiency for the given instantaneous output power requirements.
In a conventional ET PA system, varying delays may be present in the RF signal path and the envelope tracking power supply path, thus causing misalignment in the envelope tracking This misalignment is undesirable because it causes distortion of the output signal.